The interactive network television, which is also called as Internet Protocol Television (abbreviated as IPTV), refers to a general term of the devices which provide users with, via an IP bearer network, services such as the live broadcast, video on demand, time shift playing and so on of the television programs which can support interaction capability. With the development of IPTV, the number of IPTV users increases continuously, which proposes higher requirements on the systems in terms of performance and reliability and so on. In this case, as to the content delivery function of interactive network, in order to reduce the interaction between the parts of the system, it requires that the internal modules of the content interaction network have definite functions and responsibility and requires that the content delivery and service procedure are brief and reliable.
Currently, the IPTV standards are mainly based on two kinds of architectures of Next Generation Network (abbreviated as NGN) IP multimedia subsystem (abbreviated as IMS) and NGN non-IMS, which can provide video on demand, live broadcast, video recording and some new services for the users.
The content delivery network (abbreviated as CDN) in the IPTV architecture plays an important role in aspects such as quality of experience (abbreviated as QoE) guarantee and system stability in the IPTV system. Each important function entity inside the CDN is mainly used for achieving content locating technology, scheduling and storage functions.
Currently, as to the content locating technology, both the content locating and playing require to be performed by a CDN master controller, and in the situation of a large scale of users concurring, the CDN master controller may cause processing delay, thus affecting system performance and becoming a bottleneck of system performance. Although processing delay can be reduced by the manner of increasing CDN master controllers to form distributed CDN master controllers to share loads, this manner increases the complexity and building costs of the CDN master controllers.